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#define _POSIX_C_SOURCE 200809L
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "network.h"
#include "util.h"
// size of input buffer for paths and lines
#define BUF_SIZE 256
// maximum number of columns in the file
#define MAX_COLUMNS 32
// default list of interfaces to exclude
#define DEFAULT_EXCLUDE "lo"
static void *network_init(int argc, char *argv[]);
static void network_collect(scrape_req *req, void *ctx);
const struct collector network_collector = {
.name = "network",
.collect = network_collect,
.init = network_init,
.has_args = true,
};
struct network_context {
size_t ncolumns;
char *columns[MAX_COLUMNS];
struct slist *include;
struct slist *exclude;
};
static void *network_init(int argc, char *argv[]) {
// parse header from /proc/net/dev and prepare metric names
FILE *f = fopen("/proc/net/dev", "r");
if (!f) {
perror("fopen /proc/net/dev");
return 0;
}
char buf[BUF_SIZE];
char *p;
fgets_line(buf, sizeof buf, f);
p = fgets_line(buf, sizeof buf, f);
fclose(f);
if (!p) {
fprintf(stderr, "second header line in /proc/net/dev missing\n");
return 0;
}
static const char *const prefixes[2] = { "node_network_receive_", "node_network_transmit_" };
char *parts[2];
char *saveptr;
strtok_r(buf, "|", &saveptr);
parts[0] = strtok_r(0, "|", &saveptr);
parts[1] = strtok_r(0, "|", &saveptr);
p = strtok_r(0, "|", &saveptr);
if (!parts[0] || !parts[1] || p) {
fprintf(stderr, "too %s parts in /proc/net/dev header\n", p ? "many" : "few");
return 0;
}
struct network_context *ctx = malloc(sizeof *ctx);
if (!ctx) {
perror("malloc");
return 0;
}
ctx->ncolumns = 0;
for (int part = 0; part < 2; part++) {
size_t prefix_len = strlen(prefixes[part]);
for (p = strtok_r(parts[part], " \n", &saveptr); p; p = strtok_r(0, " \n", &saveptr)) {
if (ctx->ncolumns >= MAX_COLUMNS) {
fprintf(stderr, "too many columns in /proc/net/dev\n");
goto cleanup;
}
size_t header_len = strlen(p);
size_t metric_len = prefix_len + header_len + 6; // 6 for "_total"
ctx->columns[ctx->ncolumns] = malloc(metric_len + 1);
if (!ctx->columns[ctx->ncolumns]) {
perror("malloc");
goto cleanup;
}
snprintf(ctx->columns[ctx->ncolumns], metric_len + 1, "%s%s_total", prefixes[part], p);
ctx->ncolumns++;
}
}
// parse command-line arguments
ctx->include = 0;
ctx->exclude = 0;
bool exclude_set = false;
for (int arg = 0; arg < argc; arg++) {
if (strncmp(argv[arg], "include=", 8) == 0) {
ctx->include = slist_split(argv[arg] + 8, ",");
continue;
}
if (strncmp(argv[arg], "exclude=", 8) == 0) {
ctx->exclude = slist_split(argv[arg] + 8, ",");
continue;
}
fprintf(stderr, "unknown argument for network collector: %s\n", argv[arg]);
goto cleanup;
}
if (!exclude_set)
ctx->exclude = slist_split(DEFAULT_EXCLUDE, ",");
return ctx;
cleanup:
for (size_t i = 0; i < ctx->ncolumns; i++)
free(ctx->columns[i]);
free(ctx);
return 0;
}
static void network_collect(scrape_req *req, void *ctx_ptr) {
struct network_context *ctx = ctx_ptr;
// buffers
const char *labels[][2] = {
{ "device", 0 }, // filled by code
{ 0, 0 },
};
char buf[BUF_SIZE];
FILE *f;
// read network stats from /proc/net/dev
f = fopen("/proc/net/dev", "r");
if (!f)
return;
fgets_line(buf, sizeof buf, f);
fgets_line(buf, sizeof buf, f); // skipped header
while (fgets_line(buf, sizeof buf, f)) {
char *dev = buf;
while (*dev == ' ')
dev++;
char *p = strchr(dev, ':');
if (!p)
continue;
*p = '\0';
labels[0][1] = dev;
p++;
if (ctx->include) {
if (!slist_contains(ctx->include, dev))
continue;
} else if (ctx->exclude) {
if (slist_contains(ctx->exclude, dev))
continue;
}
char *saveptr;
p = strtok_r(p, " \n", &saveptr);
for (size_t i = 0; i < ctx->ncolumns && p; i++, p = strtok_r(0, " \n", &saveptr)) {
char *endptr;
double value = strtod(p, &endptr);
if (*endptr != '\0')
continue;
scrape_write(req, ctx->columns[i], labels, value);
}
}
fclose(f);
}
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